I have a 1998 Toyota Tacoma 2.7L 4cyl with 202,000. The engine has been running rough and will occasionally sputter and die when I let off the gas pedal. I had it diagnosed and they think it's a stuck valve. One of the cylinders had less than 50% compression. I was quoted a minimum of $750 in labor for a machinist to take it apart and any parts will be extra. I have been driving the truck in this condition for several hundred miles.

Am I risking further major damage or am I just getting diminished performance?

  • They think a valve is stuck? Did they do a leak down test? – Ben Jun 3 '16 at 21:20
  • Not sure. They just informed me of the pressure loss in one cylinder, as well as an exhaust leak. – flyinryan Jun 3 '16 at 21:27
  • Well at this point it's only going to get worse unless whatever the cause is is fixed. I'd suggest getting a second opinion unless you have 100% confidence in the shop. – Ben Jun 3 '16 at 21:30
  • Welcome to the site. Cheers! – DucatiKiller Jun 3 '16 at 21:37

The longer you run it, the more damage you are going to cause. This will incur more cost when you do go to get it fixed due to the parts involved. Depending on which valve(s) is (are) sticking, you could be doing damage every time you start it up. I'm talking about the exhaust valve, as if one is open during the combustion cycle, you've damaged a valve and the seat most likely. This could also be damaging your cam shaft(s) and all other valve train related parts as well. I'd suspect, though, you've already done enough damage to need replacement of these parts. When things aren't working right, they tend to wear fast. Only getting the engine apart at this point will truly tell you the extent of the damage.

I will say, though, you can probably get a rebuilt head off of eBay and have it installed for cheaper than what it would cost to get the work done at this point. That wouldn't take a machinist, just a mechanic with some knowledge. There'd be a few parts to be purchased to make it happen.

  • Excellent. I have been looking into possibly buying a rebuilt engine, but I hadn't considered buying a rebuilt head. I will look into that, thanks! – flyinryan Jun 3 '16 at 22:12
  • 1
    A misfiring cylinder will quickly damage catalytic converters. – Fred Wilson Jun 4 '16 at 0:53

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